The present inventions relate to novel mechanisms, and, as well, systems for moving fluids in a controllable, precise, accurate and advantageous fashion, generally for the purpose of developing a liquid or hydraulic pressure which will actuate a piston and piston rod to move in either of two directions; extend or retract.
For purposes of description herein the device will be described as driven by a direct current motor controlled by a three position switch or relay by which current is directed appropriately to yield motor shaft movement either clockwise, counterclockwise, or stop or at rest position.
More particularly the present invention relates to a novel and unique pump which is bi-rotational. By bi-rotational is meant a pump that has two pressure outlets connectable to opposite ends of a hydraulic cylinder containing a movable piston rod and piston therewithin capable of moving in directions as controlled by the pumps rotational movement. As indicated above the pumps rotational direction is herein described as effected by a direct current electric motor whose drive shaft rotation is dependent upon the electrical connection effected by the three-position switch or relay. Reversing polarity will reverse rotation. As can be appreciated the to and fro motion of the piston rod is of utility in effecting controlled reciprocal movement of a variety of elements as more particularly and detailedly described hereinafter.
The present invention relates most particularly to a hydraulic bi-rotational pump embodying novel feature of structure and operation which allows achievement and simplicity of operation beyond that anything known at the present time; and being capable of being constructed very small which permits its utilization in a manner unknown to the present time.
Gear pumps, of course, are well known in the art and need no present detailed description. Gear pumps are generally constructed of two intermeshing gears located in a cavity having an inlet and an outlet. In the gear pump of the present invention the structure is of such novelty and unique design as provide an inlet for the pump in the usual fashion but in accordance with the present invention has two outlets. One outlet is used to convey hydraulic oil or develop pressure through one outlet, depending on a clockwise rotation of the motor and the connected shaft on which is mounted the intermeshing gear. The other outlet is used to direct fluid pressure pursuant to counterclockwise rotation of the DC motor shaft and the connected drive shaft bearing the gears and controlling the movement and rotation of the intermeshing gears.
The novelty of the present pump may be described as due in part to its constructional details consisting of multiple parts located in flush side by side relationship; on either side of the housing containing the intermeshing gears; said side by side parts being machined to contain a novel arrangement of internal passageways interrupted by moveable ball type check valves and piston actuated valves; all operating in cooperative relationship to direct the appropriate fluid, usually a hydraulic oil, out one or the other of the two outlets connected by appropriate passageways/conduits to opposite ends of a cylinder or actuator containing the usual piston rod and piston arrangement.
The construction is such that instant and positive change of direction of the piston is achieved by appropriate actuation of the drive motor and controlled by the three-position switch, accomplishing appropriate direction of the hydraulic fluid to one side or the other of the piston in the actuator cylinder. The design and interrelationship of these cooperating parts and features are such that the entire pump body is surrounded by the hydraulic fluid and the size of the pump is extremely small (as described in more detail hereinafter) such that it can be fabricated of a large selection of materials of construction (aluminum preferred) and of a size as permits desired utilitarian functionality in a variety of applications.
While the pump of the present invention may be fabricated/constructed of a variety of materials including metals, engineering plastics, acrylonitrile/butadiene/styrene (ABS) tripolomers, etc.; aluminum is a preferred material of construction for the pump parts identified hereinafter, with the exception that the oppositely rotatable intermeshing gears and their cavity wherein located is usually desirably formed of steel by reason of its being able to endure the frictional movement of the counter rotating gears within the cavity. The pump of the present invention is desirably fabricated, at the present time (as a preferred mode), to an overall dimension of about two inches (2″) in length by about one and one quarter inches (1-1¼″) in diameter.
This is remarkably small considering the many unique and sophisticated, constructional details including the passageways which are integral to a successful operation and to the small ball and check valves (with opposing springs in some cases), as also described herein. A currently suitable and appropriate direct current motor may be selected from a variety of generally available, direct current motors whose shaft rotation is dependent upon the electrical connection to the positive and negative terminals.
It is a variant embodiment of the present invention to employ the bi-rotational pump and suitable drive motor by locating both within a hydraulic cylinder/actuator. The latter will also include a piston and piston rod driven/movable by the hydraulic pressure developed by the rotation of the intermeshing gears in the novel bi-rotational pump. The latter as described earlier and illustrated in the drawings includes two outlets which, by reason of the passageways formed in the pump on either side of the gear housing, direct fluid through appropriate passageways, to one side or the other of the piston slidably located in the actuator, so as to accomplish a linear reciprocating movement in turn depending upon the connection (via switch or relay) of the electric direct current to one or the other terminals of the motor. The latter, of course, will result in the rotating of the gears in one direction or then other thus so that pressure will be developed within the pump proper as to direct the hydraulic pressure via outlets/passageways to either one side or the other of the piston.
It will be appreciated that the hydraulic driving gear rotates directly as driven by the shaft of the direct current motor. A cooperating sister gear in intermeshing relationship with the principal driving shaft is mounted on a idler shaft located in parallel relationship with the drive shaft as above.
In accordance with a subsidiary embodiment of the present invention, the bi-rotational hydraulic pump is employed in combination with an actuator, and an electric motor driving the bi-rotational hydraulic pump, all located within the hydraulic cylinder, including provisions for an oil reserve, and forming one compact unit. This unit yields a package with no leaking connectors, no valves to operate and no maintenance over its life. The oil reserve reservoir has no connection with the outside air so no oil will be able to escape through a vent. All exposed material is aluminum except for the piston rod which is fabricated of Nitrotech steel and the electric motor.
In summary, the actuator operates as follows: when the electric D.C. Motor is rotating clockwise, the piston rod is extending from the hydraulic cylinder or actuator. When the motor is rotating counterclockwise, the piston rod is retracting into the actuator cylinder. When the electric motor is off the piston rod is hydraulically locked into position.
The combination of motor, pump, fluid reservoir and cylinder in a single package has very unique utility in constituting therefore a self-contained actuator requiring only a change in the polarity of the motor to achieve a change in the direction of the bi-rotational pump and, through its novel arrangement of passageways and ball valves, a change in the direction of the hydraulic flow such that it passes into the actuator cylinder on one side of the piston or the other.
In this fashion the movement of the piston rod is reversed to effect appropriate movement of the mechanism part or item which is desirable moved reliably in reciprocal, to and fro fashion.
A unique and novel feature and utilitarian feature is that the totality of the cylinder, of the motor and the pump in accordance with the present invention weighs little more than a conventional hydraulic cylinder for the same application.
This embodiment of the present invention wherein the novel bi-rotational pump, the hydraulic cylinder and including the drive motor in one cylinder finds particular utility in the field of recreational vehicles to control the sliding/reciprocating movement of rooms or levelers or letdown shades etc.
It can also be used in the transportation field eg. cars, vans, buses and including paraplegic lifts. The cylinder, referred to as an actuator, is also usable in lift gates, cranes, and support legs in the truck equipment business.
In the general field of industry the bi-rotational pump and reciprocal piston rod finds its utility as a door closer, as an opener of skylights, and in positioning fixturing, materials handling. Further in the field of automotive and specifically garden tractors the device is used in deck lifts as well as three-point hitch lifts. In the field of material handling, the device, in the form of the reciprocable piston controlled by hydraulic fluid described hereinabove and in more detail hereinafter finds utility in controlling belt lifts, material clamping, scissors lifts, as well as conveyor control.
In the marine environment these devices find wide acceptance in the field of driving of tilt trims, trim tabs, or the opening of skylights, etc. In the field of agriculture the device is eminently utilitarian in the control of support legs, auger control, gate closers, and implement lifts.
Presently available gear pumps are largely unsuitable in the applications described, by reason of their larger size, heavier weight, and their general inaccuracy and lack of close control as compared to the bi-rotational pumps of the present invention and as compared to the combination of the bi-rotational pump and actuator and electric motor in one compact cylinder as described herein.